Terrain detail meshes have wrong orientation

Hello Unity Community!

I'm trying to paint some detail meshes onto my terrain, but I'm running in some issue regarding the orientation of the meshes. I'm importing a .fbx that I found on the web, adding it in the texture painter and then painting with it. However, this is what shows up: The meshes appear horizontal when I paint them, while I'm trying to achieve what I highlighted with red. I think this is probably an import issue, but I have no clue on how to fix it. The imported object has a rotation of 270 on X by default for some reason. It even shows up horizontally in the inspector preview and in thumbnails. I've tried tweaking it by making the mesh a child of an empty game object, but then I couldn't paint with them any more, nothing showed up.

Feel free to ask for any details about my set-up that I might have omitted.

Thanks for your time!

• Ashky